Abstract: This paper addresses microcomputer security in the context of a transportation agency. Schemes for physical protection of hardware, such as locking workstations and alarms, are examined for the office as well as maintenance and operations facilities. Protection of removable media and software backups is discussed for single and multi-user systems. Access to small computer systems is presented on several levels. Power supply locks and passwords are discussed for single and multi-user systems. The implications of individual system compatibilities on secure shared resource access in local area networks are explored.